From lions to everything…

The Serengeti lion project was established by George Schaller in 1966; his book, The Serengeti Lion, is a classic. When I arrived in 1978, it was hard to imagine there was much left to discover about lions, and I only expected to stay in the Serengeti for a few years. I just planned to answer a few specific questions about lion behavior before moving on to the next species. My prior research had been on baboons and Japanese macaques, animals that move around a lot and interact with each other throughout the day. Lions sleep in tall grass and are mostly active at night. Watching lions is a test of patience.

I took it for granted that lions live in complex social groups (“prides” consisting of about six related females, their dependent offspring, and a coalition of 2-3 males that have joined the females from elsewhere). I wanted to know why pride females raised their cubs together in a creche; how coalition partners competed with each other for mating opportunities; how the whole crowd managed to feed together at kills.

But whereas a lot of the Serengeti lions were mating and feeding those first few years, there were very few cubs in the population, so I decided to continue the study a bit longer. But as time went by, I became ever more intrigued about the fundamental ecology of these animals. The Serengeti was changing: trees were spreading in the woodlands, the lion population grew by about 50%, but lions were getting harder to find. The study area contained a dozen prides in a thousand square kilometers; but some of the prides might not be seen for months on end. I would go out into the field for four days at time, sleeping in the Land Rover, listening for roars, hoping to see an upright lion in the early morning light.

It wasn’t until we started using radio collars in 1984 that we could find our study animals on a daily basis. The project then grew in previously unimaginable ways. We could follow lions through the night; we could see where they went when they didn’t want to be seen. And my graduate students and field assistants could hit the ground running, finding lions for themselves their very first day on the job.

We started asking harder questions: Why did lions live in those complex groups? Why did the males have manes? Who fathered the cubs within the pride? What sort of diseases did they catch – and why were some outbreaks more deadly than others?

By then we tracked close to two-dozen prides, and our focus remained primarily on the lions – on their social behavior, their genetics and epidemiology. It has only been in the past few years that I’ve felt comfortable about expanding our research program into a broader perspective. Although there are several other long-term studies in the Serengeti, none of them are able to measure their species’ movements in the same degree of detail as the lions. Cheetah biologists drive around looking for cheetah with patient optimism; hyena biologists watch hyenas at den sites then accept that their nocturnal subjects will wander off to points unknown during the night. And no one keeps track of individual topi, hartebeest, waterbuck, bushbuck, impala or dikdik – let alone knows the daily life of a specific wildebeest, zebra or gazelle… There’s not enough research funding in the world to attach enough radio collars on all those species, and it probably wouldn’t be a good idea to tag any of the herbivores who might then stand out a mile in a lion’s territory.

Then we realized that we didn’t have to touch a thing. We just needed to set up enough camera-traps to get a composite snapshot of the Serengeti. We received generous funding from the National Science Foundation, which allowed us to set out 225 camera-traps in our study area, but then we faced the problem of how to process the resultant flood of over a million photos a year…